Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfashe...
[linux-2.6] / fs / ecryptfs / mmap.c
1 /**
2  * eCryptfs: Linux filesystem encryption layer
3  * This is where eCryptfs coordinates the symmetric encryption and
4  * decryption of the file data as it passes between the lower
5  * encrypted file and the upper decrypted file.
6  *
7  * Copyright (C) 1997-2003 Erez Zadok
8  * Copyright (C) 2001-2003 Stony Brook University
9  * Copyright (C) 2004-2006 International Business Machines Corp.
10  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
11  *
12  * This program is free software; you can redistribute it and/or
13  * modify it under the terms of the GNU General Public License as
14  * published by the Free Software Foundation; either version 2 of the
15  * License, or (at your option) any later version.
16  *
17  * This program is distributed in the hope that it will be useful, but
18  * WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20  * General Public License for more details.
21  *
22  * You should have received a copy of the GNU General Public License
23  * along with this program; if not, write to the Free Software
24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
25  * 02111-1307, USA.
26  */
27
28 #include <linux/pagemap.h>
29 #include <linux/writeback.h>
30 #include <linux/page-flags.h>
31 #include <linux/mount.h>
32 #include <linux/file.h>
33 #include <linux/crypto.h>
34 #include <linux/scatterlist.h>
35 #include "ecryptfs_kernel.h"
36
37 struct kmem_cache *ecryptfs_lower_page_cache;
38
39 /**
40  * ecryptfs_get1page
41  *
42  * Get one page from cache or lower f/s, return error otherwise.
43  *
44  * Returns unlocked and up-to-date page (if ok), with increased
45  * refcnt.
46  */
47 static struct page *ecryptfs_get1page(struct file *file, int index)
48 {
49         struct page *page;
50         struct dentry *dentry;
51         struct inode *inode;
52         struct address_space *mapping;
53
54         dentry = file->f_path.dentry;
55         inode = dentry->d_inode;
56         mapping = inode->i_mapping;
57         page = read_cache_page(mapping, index,
58                                (filler_t *)mapping->a_ops->readpage,
59                                (void *)file);
60         if (IS_ERR(page))
61                 goto out;
62         wait_on_page_locked(page);
63 out:
64         return page;
65 }
66
67 static
68 int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros);
69
70 /**
71  * ecryptfs_fill_zeros
72  * @file: The ecryptfs file
73  * @new_length: The new length of the data in the underlying file;
74  *              everything between the prior end of the file and the
75  *              new end of the file will be filled with zero's.
76  *              new_length must be greater than  current length
77  *
78  * Function for handling lseek-ing past the end of the file.
79  *
80  * This function does not support shrinking, only growing a file.
81  *
82  * Returns zero on success; non-zero otherwise.
83  */
84 int ecryptfs_fill_zeros(struct file *file, loff_t new_length)
85 {
86         int rc = 0;
87         struct dentry *dentry = file->f_path.dentry;
88         struct inode *inode = dentry->d_inode;
89         pgoff_t old_end_page_index = 0;
90         pgoff_t index = old_end_page_index;
91         int old_end_pos_in_page = -1;
92         pgoff_t new_end_page_index;
93         int new_end_pos_in_page;
94         loff_t cur_length = i_size_read(inode);
95
96         if (cur_length != 0) {
97                 index = old_end_page_index =
98                     ((cur_length - 1) >> PAGE_CACHE_SHIFT);
99                 old_end_pos_in_page = ((cur_length - 1) & ~PAGE_CACHE_MASK);
100         }
101         new_end_page_index = ((new_length - 1) >> PAGE_CACHE_SHIFT);
102         new_end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK);
103         ecryptfs_printk(KERN_DEBUG, "old_end_page_index = [0x%.16x]; "
104                         "old_end_pos_in_page = [%d]; "
105                         "new_end_page_index = [0x%.16x]; "
106                         "new_end_pos_in_page = [%d]\n",
107                         old_end_page_index, old_end_pos_in_page,
108                         new_end_page_index, new_end_pos_in_page);
109         if (old_end_page_index == new_end_page_index) {
110                 /* Start and end are in the same page; we just need to
111                  * set a portion of the existing page to zero's */
112                 rc = write_zeros(file, index, (old_end_pos_in_page + 1),
113                                  (new_end_pos_in_page - old_end_pos_in_page));
114                 if (rc)
115                         ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
116                                         "index=[0x%.16x], "
117                                         "old_end_pos_in_page=[d], "
118                                         "(PAGE_CACHE_SIZE - new_end_pos_in_page"
119                                         "=[%d]"
120                                         ")=[d]) returned [%d]\n", file, index,
121                                         old_end_pos_in_page,
122                                         new_end_pos_in_page,
123                                         (PAGE_CACHE_SIZE - new_end_pos_in_page),
124                                         rc);
125                 goto out;
126         }
127         /* Fill the remainder of the previous last page with zeros */
128         rc = write_zeros(file, index, (old_end_pos_in_page + 1),
129                          ((PAGE_CACHE_SIZE - 1) - old_end_pos_in_page));
130         if (rc) {
131                 ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
132                                 "index=[0x%.16x], old_end_pos_in_page=[d], "
133                                 "(PAGE_CACHE_SIZE - old_end_pos_in_page)=[d]) "
134                                 "returned [%d]\n", file, index,
135                                 old_end_pos_in_page,
136                                 (PAGE_CACHE_SIZE - old_end_pos_in_page), rc);
137                 goto out;
138         }
139         index++;
140         while (index < new_end_page_index) {
141                 /* Fill all intermediate pages with zeros */
142                 rc = write_zeros(file, index, 0, PAGE_CACHE_SIZE);
143                 if (rc) {
144                         ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], "
145                                         "index=[0x%.16x], "
146                                         "old_end_pos_in_page=[d], "
147                                         "(PAGE_CACHE_SIZE - new_end_pos_in_page"
148                                         "=[%d]"
149                                         ")=[d]) returned [%d]\n", file, index,
150                                         old_end_pos_in_page,
151                                         new_end_pos_in_page,
152                                         (PAGE_CACHE_SIZE - new_end_pos_in_page),
153                                         rc);
154                         goto out;
155                 }
156                 index++;
157         }
158         /* Fill the portion at the beginning of the last new page with
159          * zero's */
160         rc = write_zeros(file, index, 0, (new_end_pos_in_page + 1));
161         if (rc) {
162                 ecryptfs_printk(KERN_ERR, "write_zeros(file="
163                                 "[%p], index=[0x%.16x], 0, "
164                                 "new_end_pos_in_page=[%d]"
165                                 "returned [%d]\n", file, index,
166                                 new_end_pos_in_page, rc);
167                 goto out;
168         }
169 out:
170         return rc;
171 }
172
173 /**
174  * ecryptfs_writepage
175  * @page: Page that is locked before this call is made
176  *
177  * Returns zero on success; non-zero otherwise
178  */
179 static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
180 {
181         struct ecryptfs_page_crypt_context ctx;
182         int rc;
183
184         ctx.page = page;
185         ctx.mode = ECRYPTFS_WRITEPAGE_MODE;
186         ctx.param.wbc = wbc;
187         rc = ecryptfs_encrypt_page(&ctx);
188         if (rc) {
189                 ecryptfs_printk(KERN_WARNING, "Error encrypting "
190                                 "page (upper index [0x%.16x])\n", page->index);
191                 ClearPageUptodate(page);
192                 goto out;
193         }
194         SetPageUptodate(page);
195         unlock_page(page);
196 out:
197         return rc;
198 }
199
200 /**
201  * Reads the data from the lower file file at index lower_page_index
202  * and copies that data into page.
203  *
204  * @param page  Page to fill
205  * @param lower_page_index Index of the page in the lower file to get
206  */
207 int ecryptfs_do_readpage(struct file *file, struct page *page,
208                          pgoff_t lower_page_index)
209 {
210         int rc;
211         struct dentry *dentry;
212         struct file *lower_file;
213         struct dentry *lower_dentry;
214         struct inode *inode;
215         struct inode *lower_inode;
216         char *page_data;
217         struct page *lower_page = NULL;
218         char *lower_page_data;
219         const struct address_space_operations *lower_a_ops;
220
221         dentry = file->f_path.dentry;
222         lower_file = ecryptfs_file_to_lower(file);
223         lower_dentry = ecryptfs_dentry_to_lower(dentry);
224         inode = dentry->d_inode;
225         lower_inode = ecryptfs_inode_to_lower(inode);
226         lower_a_ops = lower_inode->i_mapping->a_ops;
227         lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index,
228                                      (filler_t *)lower_a_ops->readpage,
229                                      (void *)lower_file);
230         if (IS_ERR(lower_page)) {
231                 rc = PTR_ERR(lower_page);
232                 lower_page = NULL;
233                 ecryptfs_printk(KERN_ERR, "Error reading from page cache\n");
234                 goto out;
235         }
236         wait_on_page_locked(lower_page);
237         page_data = (char *)kmap(page);
238         if (!page_data) {
239                 rc = -ENOMEM;
240                 ecryptfs_printk(KERN_ERR, "Error mapping page\n");
241                 goto out;
242         }
243         lower_page_data = (char *)kmap(lower_page);
244         if (!lower_page_data) {
245                 rc = -ENOMEM;
246                 ecryptfs_printk(KERN_ERR, "Error mapping page\n");
247                 kunmap(page);
248                 goto out;
249         }
250         memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
251         kunmap(lower_page);
252         kunmap(page);
253         rc = 0;
254 out:
255         if (likely(lower_page))
256                 page_cache_release(lower_page);
257         if (rc == 0)
258                 SetPageUptodate(page);
259         else
260                 ClearPageUptodate(page);
261         return rc;
262 }
263
264 /**
265  * ecryptfs_readpage
266  * @file: This is an ecryptfs file
267  * @page: ecryptfs associated page to stick the read data into
268  *
269  * Read in a page, decrypting if necessary.
270  *
271  * Returns zero on success; non-zero on error.
272  */
273 static int ecryptfs_readpage(struct file *file, struct page *page)
274 {
275         int rc = 0;
276         struct ecryptfs_crypt_stat *crypt_stat;
277
278         BUG_ON(!(file && file->f_path.dentry && file->f_path.dentry->d_inode));
279         crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
280                         ->crypt_stat;
281         if (!crypt_stat
282             || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED)
283             || ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE)) {
284                 ecryptfs_printk(KERN_DEBUG,
285                                 "Passing through unencrypted page\n");
286                 rc = ecryptfs_do_readpage(file, page, page->index);
287                 if (rc) {
288                         ecryptfs_printk(KERN_ERR, "Error reading page; rc = "
289                                         "[%d]\n", rc);
290                         goto out;
291                 }
292         } else {
293                 rc = ecryptfs_decrypt_page(file, page);
294                 if (rc) {
295
296                         ecryptfs_printk(KERN_ERR, "Error decrypting page; "
297                                         "rc = [%d]\n", rc);
298                         goto out;
299                 }
300         }
301         SetPageUptodate(page);
302 out:
303         if (rc)
304                 ClearPageUptodate(page);
305         ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
306                         page->index);
307         unlock_page(page);
308         return rc;
309 }
310
311 static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
312 {
313         struct inode *inode = page->mapping->host;
314         int end_byte_in_page;
315         int rc = 0;
316         char *page_virt;
317
318         if ((i_size_read(inode) / PAGE_CACHE_SIZE) == page->index) {
319                 end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
320                 if (to > end_byte_in_page)
321                         end_byte_in_page = to;
322                 page_virt = kmap(page);
323                 if (!page_virt) {
324                         rc = -ENOMEM;
325                         ecryptfs_printk(KERN_WARNING,
326                                         "Could not map page\n");
327                         goto out;
328                 }
329                 memset((page_virt + end_byte_in_page), 0,
330                        (PAGE_CACHE_SIZE - end_byte_in_page));
331                 kunmap(page);
332         }
333 out:
334         return rc;
335 }
336
337 static int ecryptfs_prepare_write(struct file *file, struct page *page,
338                                   unsigned from, unsigned to)
339 {
340         int rc = 0;
341
342         kmap(page);
343         if (from == 0 && to == PAGE_CACHE_SIZE)
344                 goto out;       /* If we are writing a full page, it will be
345                                    up to date. */
346         if (!PageUptodate(page))
347                 rc = ecryptfs_do_readpage(file, page, page->index);
348 out:
349         return rc;
350 }
351
352 int ecryptfs_grab_and_map_lower_page(struct page **lower_page,
353                                      char **lower_virt,
354                                      struct inode *lower_inode,
355                                      unsigned long lower_page_index)
356 {
357         int rc = 0;
358
359         (*lower_page) = grab_cache_page(lower_inode->i_mapping,
360                                         lower_page_index);
361         if (!(*lower_page)) {
362                 ecryptfs_printk(KERN_ERR, "grab_cache_page for "
363                                 "lower_page_index = [0x%.16x] failed\n",
364                                 lower_page_index);
365                 rc = -EINVAL;
366                 goto out;
367         }
368         if (lower_virt)
369                 (*lower_virt) = kmap((*lower_page));
370         else
371                 kmap((*lower_page));
372 out:
373         return rc;
374 }
375
376 int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
377                                               struct inode *lower_inode,
378                                               struct writeback_control *wbc)
379 {
380         int rc = 0;
381
382         rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc);
383         if (rc) {
384                 ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); "
385                                 "rc = [%d]\n", rc);
386                 goto out;
387         }
388         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
389         page_cache_release(lower_page);
390 out:
391         return rc;
392 }
393
394 static void ecryptfs_unmap_and_release_lower_page(struct page *lower_page)
395 {
396         kunmap(lower_page);
397         ecryptfs_printk(KERN_DEBUG, "Unlocking lower page with index = "
398                         "[0x%.16x]\n", lower_page->index);
399         unlock_page(lower_page);
400         page_cache_release(lower_page);
401 }
402
403 /**
404  * ecryptfs_write_inode_size_to_header
405  *
406  * Writes the lower file size to the first 8 bytes of the header.
407  *
408  * Returns zero on success; non-zero on error.
409  */
410 int
411 ecryptfs_write_inode_size_to_header(struct file *lower_file,
412                                     struct inode *lower_inode,
413                                     struct inode *inode)
414 {
415         int rc = 0;
416         struct page *header_page;
417         char *header_virt;
418         const struct address_space_operations *lower_a_ops;
419         u64 file_size;
420
421         rc = ecryptfs_grab_and_map_lower_page(&header_page, &header_virt,
422                                               lower_inode, 0);
423         if (rc) {
424                 ecryptfs_printk(KERN_ERR, "grab_cache_page for header page "
425                                 "failed\n");
426                 goto out;
427         }
428         lower_a_ops = lower_inode->i_mapping->a_ops;
429         rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8);
430         file_size = (u64)i_size_read(inode);
431         ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size);
432         file_size = cpu_to_be64(file_size);
433         memcpy(header_virt, &file_size, sizeof(u64));
434         rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8);
435         if (rc < 0)
436                 ecryptfs_printk(KERN_ERR, "Error commiting header page "
437                                 "write\n");
438         ecryptfs_unmap_and_release_lower_page(header_page);
439         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
440         mark_inode_dirty_sync(inode);
441 out:
442         return rc;
443 }
444
445 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
446                             struct file *lower_file,
447                             unsigned long lower_page_index, int byte_offset,
448                             int region_bytes)
449 {
450         int rc = 0;
451
452         rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL, lower_inode,
453                                               lower_page_index);
454         if (rc) {
455                 ecryptfs_printk(KERN_ERR, "Error attempting to grab and map "
456                                 "lower page with index [0x%.16x]\n",
457                                 lower_page_index);
458                 goto out;
459         }
460         rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file,
461                                                           (*lower_page),
462                                                           byte_offset,
463                                                           region_bytes);
464         if (rc) {
465                 ecryptfs_printk(KERN_ERR, "prepare_write for "
466                                 "lower_page_index = [0x%.16x] failed; rc = "
467                                 "[%d]\n", lower_page_index, rc);
468         }
469 out:
470         if (rc && (*lower_page)) {
471                 ecryptfs_unmap_and_release_lower_page(*lower_page);
472                 (*lower_page) = NULL;
473         }
474         return rc;
475 }
476
477 /**
478  * ecryptfs_commit_lower_page
479  *
480  * Returns zero on success; non-zero on error
481  */
482 int
483 ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
484                            struct file *lower_file, int byte_offset,
485                            int region_size)
486 {
487         int rc = 0;
488
489         rc = lower_inode->i_mapping->a_ops->commit_write(
490                 lower_file, lower_page, byte_offset, region_size);
491         if (rc < 0) {
492                 ecryptfs_printk(KERN_ERR,
493                                 "Error committing write; rc = [%d]\n", rc);
494         } else
495                 rc = 0;
496         ecryptfs_unmap_and_release_lower_page(lower_page);
497         return rc;
498 }
499
500 /**
501  * ecryptfs_copy_page_to_lower
502  *
503  * Used for plaintext pass-through; no page index interpolation
504  * required.
505  */
506 int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
507                                 struct file *lower_file)
508 {
509         int rc = 0;
510         struct page *lower_page;
511
512         rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file,
513                                      page->index, 0, PAGE_CACHE_SIZE);
514         if (rc) {
515                 ecryptfs_printk(KERN_ERR, "Error attempting to get page "
516                                 "at index [0x%.16x]\n", page->index);
517                 goto out;
518         }
519         /* TODO: aops */
520         memcpy((char *)page_address(lower_page), page_address(page),
521                PAGE_CACHE_SIZE);
522         rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file,
523                                         0, PAGE_CACHE_SIZE);
524         if (rc)
525                 ecryptfs_printk(KERN_ERR, "Error attempting to commit page "
526                                 "at index [0x%.16x]\n", page->index);
527 out:
528         return rc;
529 }
530
531 static int
532 process_new_file(struct ecryptfs_crypt_stat *crypt_stat,
533                  struct file *file, struct inode *inode)
534 {
535         struct page *header_page;
536         const struct address_space_operations *lower_a_ops;
537         struct inode *lower_inode;
538         struct file *lower_file;
539         char *header_virt;
540         int rc = 0;
541         int current_header_page = 0;
542         int header_pages;
543         int more_header_data_to_be_written = 1;
544
545         lower_inode = ecryptfs_inode_to_lower(inode);
546         lower_file = ecryptfs_file_to_lower(file);
547         lower_a_ops = lower_inode->i_mapping->a_ops;
548         header_pages = ((crypt_stat->header_extent_size
549                          * crypt_stat->num_header_extents_at_front)
550                         / PAGE_CACHE_SIZE);
551         BUG_ON(header_pages < 1);
552         while (current_header_page < header_pages) {
553                 rc = ecryptfs_grab_and_map_lower_page(&header_page,
554                                                       &header_virt,
555                                                       lower_inode,
556                                                       current_header_page);
557                 if (rc) {
558                         ecryptfs_printk(KERN_ERR, "grab_cache_page for "
559                                         "header page [%d] failed; rc = [%d]\n",
560                                         current_header_page, rc);
561                         goto out;
562                 }
563                 rc = lower_a_ops->prepare_write(lower_file, header_page, 0,
564                                                 PAGE_CACHE_SIZE);
565                 if (rc) {
566                         ecryptfs_printk(KERN_ERR, "Error preparing to write "
567                                         "header page out; rc = [%d]\n", rc);
568                         goto out;
569                 }
570                 memset(header_virt, 0, PAGE_CACHE_SIZE);
571                 if (more_header_data_to_be_written) {
572                         rc = ecryptfs_write_headers_virt(header_virt,
573                                                          crypt_stat,
574                                                          file->f_dentry);
575                         if (rc) {
576                                 ecryptfs_printk(KERN_WARNING, "Error "
577                                                 "generating header; rc = "
578                                                 "[%d]\n", rc);
579                                 rc = -EIO;
580                                 memset(header_virt, 0, PAGE_CACHE_SIZE);
581                                 ecryptfs_unmap_and_release_lower_page(
582                                         header_page);
583                                 goto out;
584                         }
585                         if (current_header_page == 0)
586                                 memset(header_virt, 0, 8);
587                         more_header_data_to_be_written = 0;
588                 }
589                 rc = lower_a_ops->commit_write(lower_file, header_page, 0,
590                                                PAGE_CACHE_SIZE);
591                 ecryptfs_unmap_and_release_lower_page(header_page);
592                 if (rc < 0) {
593                         ecryptfs_printk(KERN_ERR,
594                                         "Error commiting header page write; "
595                                         "rc = [%d]\n", rc);
596                         break;
597                 }
598                 current_header_page++;
599         }
600         if (rc >= 0) {
601                 rc = 0;
602                 ecryptfs_printk(KERN_DEBUG, "lower_inode->i_blocks = "
603                                 "[0x%.16x]\n", lower_inode->i_blocks);
604                 i_size_write(inode, 0);
605                 lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
606                 mark_inode_dirty_sync(inode);
607         }
608         ecryptfs_printk(KERN_DEBUG, "Clearing ECRYPTFS_NEW_FILE flag in "
609                         "crypt_stat at memory location [%p]\n", crypt_stat);
610         ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE);
611 out:
612         return rc;
613 }
614
615 /**
616  * ecryptfs_commit_write
617  * @file: The eCryptfs file object
618  * @page: The eCryptfs page
619  * @from: Ignored (we rotate the page IV on each write)
620  * @to: Ignored
621  *
622  * This is where we encrypt the data and pass the encrypted data to
623  * the lower filesystem.  In OpenPGP-compatible mode, we operate on
624  * entire underlying packets.
625  */
626 static int ecryptfs_commit_write(struct file *file, struct page *page,
627                                  unsigned from, unsigned to)
628 {
629         struct ecryptfs_page_crypt_context ctx;
630         loff_t pos;
631         struct inode *inode;
632         struct inode *lower_inode;
633         struct file *lower_file;
634         struct ecryptfs_crypt_stat *crypt_stat;
635         int rc;
636
637         inode = page->mapping->host;
638         lower_inode = ecryptfs_inode_to_lower(inode);
639         lower_file = ecryptfs_file_to_lower(file);
640         mutex_lock(&lower_inode->i_mutex);
641         crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
642                                 ->crypt_stat;
643         if (ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE)) {
644                 ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in "
645                         "crypt_stat at memory location [%p]\n", crypt_stat);
646                 rc = process_new_file(crypt_stat, file, inode);
647                 if (rc) {
648                         ecryptfs_printk(KERN_ERR, "Error processing new "
649                                         "file; rc = [%d]\n", rc);
650                         goto out;
651                 }
652         } else
653                 ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
654         ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
655                         "(page w/ index = [0x%.16x], to = [%d])\n", page->index,
656                         to);
657         rc = fill_zeros_to_end_of_page(page, to);
658         if (rc) {
659                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
660                                 "zeros in page with index = [0x%.16x]\n",
661                                 page->index);
662                 goto out;
663         }
664         ctx.page = page;
665         ctx.mode = ECRYPTFS_PREPARE_COMMIT_MODE;
666         ctx.param.lower_file = lower_file;
667         rc = ecryptfs_encrypt_page(&ctx);
668         if (rc) {
669                 ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
670                                 "index [0x%.16x])\n", page->index);
671                 goto out;
672         }
673         rc = 0;
674         inode->i_blocks = lower_inode->i_blocks;
675         pos = (page->index << PAGE_CACHE_SHIFT) + to;
676         if (pos > i_size_read(inode)) {
677                 i_size_write(inode, pos);
678                 ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
679                                 "[0x%.16x]\n", i_size_read(inode));
680         }
681         ecryptfs_write_inode_size_to_header(lower_file, lower_inode, inode);
682         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
683         mark_inode_dirty_sync(inode);
684 out:
685         kunmap(page); /* mapped in prior call (prepare_write) */
686         if (rc < 0)
687                 ClearPageUptodate(page);
688         else
689                 SetPageUptodate(page);
690         mutex_unlock(&lower_inode->i_mutex);
691         return rc;
692 }
693
694 /**
695  * write_zeros
696  * @file: The ecryptfs file
697  * @index: The index in which we are writing
698  * @start: The position after the last block of data
699  * @num_zeros: The number of zeros to write
700  *
701  * Write a specified number of zero's to a page.
702  *
703  * (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE
704  */
705 static
706 int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros)
707 {
708         int rc = 0;
709         struct page *tmp_page;
710
711         tmp_page = ecryptfs_get1page(file, index);
712         if (IS_ERR(tmp_page)) {
713                 ecryptfs_printk(KERN_ERR, "Error getting page at index "
714                                 "[0x%.16x]\n", index);
715                 rc = PTR_ERR(tmp_page);
716                 goto out;
717         }
718         kmap(tmp_page);
719         rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros);
720         if (rc) {
721                 ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
722                                 "to remainder of page at index [0x%.16x]\n",
723                                 index);
724                 kunmap(tmp_page);
725                 page_cache_release(tmp_page);
726                 goto out;
727         }
728         memset(((char *)page_address(tmp_page) + start), 0, num_zeros);
729         rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros);
730         if (rc < 0) {
731                 ecryptfs_printk(KERN_ERR, "Error attempting to write zero's "
732                                 "to remainder of page at index [0x%.16x]\n",
733                                 index);
734                 kunmap(tmp_page);
735                 page_cache_release(tmp_page);
736                 goto out;
737         }
738         rc = 0;
739         kunmap(tmp_page);
740         page_cache_release(tmp_page);
741 out:
742         return rc;
743 }
744
745 static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
746 {
747         int rc = 0;
748         struct inode *inode;
749         struct inode *lower_inode;
750
751         inode = (struct inode *)mapping->host;
752         lower_inode = ecryptfs_inode_to_lower(inode);
753         if (lower_inode->i_mapping->a_ops->bmap)
754                 rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping,
755                                                          block);
756         return rc;
757 }
758
759 static void ecryptfs_sync_page(struct page *page)
760 {
761         struct inode *inode;
762         struct inode *lower_inode;
763         struct page *lower_page;
764
765         inode = page->mapping->host;
766         lower_inode = ecryptfs_inode_to_lower(inode);
767         /* NOTE: Recently swapped with grab_cache_page(), since
768          * sync_page() just makes sure that pending I/O gets done. */
769         lower_page = find_lock_page(lower_inode->i_mapping, page->index);
770         if (!lower_page) {
771                 ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n");
772                 return;
773         }
774         lower_page->mapping->a_ops->sync_page(lower_page);
775         ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
776                         lower_page->index);
777         unlock_page(lower_page);
778         page_cache_release(lower_page);
779 }
780
781 struct address_space_operations ecryptfs_aops = {
782         .writepage = ecryptfs_writepage,
783         .readpage = ecryptfs_readpage,
784         .prepare_write = ecryptfs_prepare_write,
785         .commit_write = ecryptfs_commit_write,
786         .bmap = ecryptfs_bmap,
787         .sync_page = ecryptfs_sync_page,
788 };